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Cranes and Slings Major Causes of Crane Accidents Contact with power lines Overturns Falls Mechanical failures 1.

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Presentation on theme: "Cranes and Slings Major Causes of Crane Accidents Contact with power lines Overturns Falls Mechanical failures 1."— Presentation transcript:

1 Cranes and Slings Major Causes of Crane Accidents Contact with power lines Overturns Falls Mechanical failures 1

2 Crane Hazards An unstable load, lack of communication, lack of training, and inadequate maintenance or inspection are major contributors to crane accidents. Operators or others working in the area can be victims to “struck by" and "caught in" injuries. Contact with power lines causes many accidents. 2

3 Crane Hazards 3 Improper loading Excessive speeds No hand signals Inadequate inspection and maintenance Unguarded parts Unguarded swing radius Working too close to power lines Improper exhaust system Shattered windows No steps/guardrails walkways No boom angle indicator Not using outriggers

4 Crane Parts 4

5 Rated Capacities Make sure the crane operator can see the: – Rated Load Capacities – Operating Speeds – Special Hazard Warning or Instruction APPLICABLE OSHA STANDARD – (a)(2) Rated load capacities, and recommended operating speeds, special hazard warnings, or instruction, shall be conspicuously posted on all equipment. Instructions or warnings shall be visible to the operator while he is at his control station. 5

6 Competent Person The competent person must inspect all machinery and equipment prior to each use, and during use, to make sure it is in safe operating condition. If it needs fixing, take it out of service and don’t use it until it is fixed 6

7 Know the Weight of the Load Refer to shipping ticket or other documentation Ensure lift calculations are correct Ensure load is within load chart rating for boom length and load radius of crane Crane is rated by the maximum weight it will lift at a minimum radius and minimum boom length – the further from its centerpoint, the less it will lift 7

8 Load Limiting Factors Not level Wind Side loads On its wheels Lifting over the side Use of extensions, jibs and other attachments Limits of wire rope, slings and lifting devices 8

9 Load Example – 30 ton crane Will lift 60,000 pounds at 10 feet from the center pin of the crane Based on level surface, no wind, and outriggers fully extended At 25 feet from the center pin with an 80 foot boom, the capacity is only 14,950 pounds At 74 feet from the center pin, the capacity is only 4,800 pounds 9

10 Wire Rope Slings 10

11 11 Adapts to shape of the load Can damage by sudden shocks Best choice for hoisting very hot materials Must have an affixed tag stating size, grade, rated capacity, and sling manufacturer Alloy Steel Chains

12 12 Chain Wear When a chain shows excessive wear, or is cracked or pitted, remove it from service Non-alloy repair links can not be used

13 Wire Rope Slings Used to hoist materials Selection considerations:  strength  ability to bend without cracking  ability to withstand abrasive wear  ability to withstand abuse 13 Wire rope Strand Center Wire Core

14 Damaged wire rope 14 Broken Strands Damaged wire rope must be taken out of service Crushed Rope

15 15 Cover or blunt protruding ends of strands Protruding Ends

16 16 Wire Rope Clips When using U-bolt wire rope clips to form eyes, ensure the "U" section is in contact with the dead end of the rope This is the correct method Dead End

17 17 Wire Rope Slings Remove From Service If these happen, remove the wire rope sling from service Crushing Kinking Bird Caging

18 Synthetic Web Sling Markings Mark or code to show: – Name or trademark of manufacturer – Rated capacities for the type of hitch – Type of material 18

19 Synthetic Web Sling Stitching Stitching is the only method allowed to attach end fittings to webbing, or to form eyes 19 Stitching

20 Synthetic Web Slings - Remove from Service Remove from service if any of these are present: – Acid or caustic burns – Melting or charring of any part – Snags, punctures, tears or cuts – Broken or worn stitches – Distortion of fittings 20 Heat Damage

21 Sling Tables 21

22 Sling Stress Example From the table, a single branch with a 90 degree loading is rated at 3,250 lbs. If there is a safety factor of 4, the chain could lift 22


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